Copper alloy strip material for electrical/electronic components

ABSTRACT

An copper alloy strip material for electrical/electronic components according to the present invention is characterized in that such the copper alloy strip material for electrical/electronic components includes: Ni as between 1.5 mass % and 4.0 mass %; Si as between 0.3 mass % and 1.5 mass %; and the balance being Cu and unavoidable impurities, wherein a mean roughness Ra of a surface roughness is not larger than 0.3 μm regarding the strip in a direction as right angle to a direction of a rolling therefor, a maximum height Ry thereof is not higher than 3.0 μm regarding the same therein, and there is positioned a peak position regarding a frequency curve, that represents a concave component of the surface roughness and/or a convex component thereof, at the plus side (the side for the convex component) comparing to an average value of the curve for meaning the surface roughness.

TECHNICAL FIELD

The present invention relates to a copper alloy strip material.

BACKGROUND ART

So far, as a material for an electrical machinery and apparatus and forelectronic equipment in general, there is widely made use of acopper-based material, as that is superior in electrical conductionproperty and in thermal conductivity, such as phosphor bronze, tombac,brass, or the like, in addition to a iron-based material.

In recent years, there becomes to be further required for packaging as asmaller in size of the electrical machinery and apparatus and of theelectronic equipment, for lighter in weight thereof, and for packagingas higher density according thereto. And then thereby there becomes tobe required a variety of properties for such the copper-based materialto be applied thereto. Here, it is able to be provided as a principalproperty therefor, such as a strength thereof, an electricalconductivity thereof, a withstand stress and relaxation characteristic,a bending workability, a pressing workability, or the like, and then inaddition thereto, it is able to be provided a surface property thereonas well, such as ability of plating thereon, a solder wettabilitythereon, or the like.

Moreover, among such the above mentioned materials, an alloy which is socalled a Corson alloy, that there is designed to be added Ni and Si intoCu, and then that there becomes to be formed a precipitate to beconfigured by making use of such the Ni and the Si therein for enhancinga strength thereof, has a potential to be enhanced such the strengththereof as extremely higher comparing to any other alloys ofprecipitation type as there are existing a plurality thereof. And thenthereby the same has already been made use for some alloys on the marketas well, such as for the CDA70250 that is the alloy of registry at theCDA (Copper Development Association), or the like.

Further, regarding such the copper alloy for the electronic equipments,there are provided the following example as heretofore known that thereis specified a relative roughness on a surface thereof regarding suchthe Corson alloy as mentioned above.

Here, the Japanese Patent Application Publication No. S63 (1988)-324782and the Japanese Patent Application Publication No. H11 (1999)-124698are individually characterized in that it becomes able to be performed aconnection of such as a gold wire or the like thereby to the copperalloy without performing a plating thereon regarding a process forproducing a semiconductor with making use of the lead frame. Stillfurther, the application according to the Japanese Patent ApplicationPublication No. 2000-288991 is for a foil, and then the same is thetechnology that is made use for an FPC (a flexible printed circuit).Still further, the application according to the Japanese PatentApplication Publication No. 2001-100581 is defined the roughness inintermediate process. Still further, there is disclosed the improvementof the solder wettability according to such the Japanese PatentApplication Publication No. H11-124698, however, there is not disclosedany embodiments at all, such as an improvement as how much degree ofmagnitude thereby. Still further, in the case of the application for thelead frame, there are disclosed the several examples, that there isperformed the assessment of the adherence regarding the oxide film layerthereon, for the object to improve the adherence onto the resin mold.

Still further, according to such the above mentioned patent documents,there is specified by making use of such as a mean roughness (Ra) of anaverage line regarding a relative roughness on a surface thereof, amaximum height (Ry) thereof, or the like. However, there is notdisclosed any relationship at all therein to a surface property, such asthe ability of plating thereon, the solder wettability thereon, or thelike, regarding each of a convex component and a concave component insuch the relative roughness on the surface thereof respectively.

Still further, regarding the Cu—Ni—Si alloy (the Corson alloy), therebecomes to be improved the strength thereof and the electricalconductivity thereof, by performing a heat treatment therefor, and thendue to occurring the precipitation of the Ni and the Si thereby as anintermetallic compound of Ni—Si therein, that are the components to becontained therein. However, there is designed to be performed such theheat treatment therefor at relatively higher temperature in general,such as between 400° C. and 600° C. Still further, there is designed tobe performed the same with an amount of time therefor as a long periodof time as well, such as between 0.5 hour and five hours. Hence, the Siin a vicinity of the surface of such the material becomes to combinethereby with oxygen as a very small amount thereof at an inside of afurnace for such the heat treatment, and then thereby there becomes tobe formed a compound of silicon oxides therein.

Still further, such the Si in the vicinity of the surface thereof cannothelp but be oxidized as similar thereto, because there is designed to beperformed at a temperature to be as further higher regarding a solutionheat treatment therefor (there may be a case where such the treatment isreferred to as a treatment for re-crystallization thereof, or atreatment for homogenization thereof).

Still further, there is heretofore known that there becomes to bedeteriorated excessively regarding such as the ability of platingthereon, the solder wettability thereon, or the like, in a case wherethere are remained such the compounds of silicon oxides even in thefinal product. And then thereby there is designed to be performed aprocess for removing the compound of silicon oxides in the vicinity ofthe surface thereof before finishing to be produced as such the finalproduct.

Still further, for removing such the compounds of silicon oxides, thereare a lot of cases where there is made use of an acid dissolution (asolution of a hydrofluoric acid based, a mixed acid solution of a dilutesulfuric acid and of a hydrogen peroxide solution) therefor. Stillfurther, there is designed to be removed such the compound withperforming a continuous strip leaping normally, that a strip of a coilshape is soaked into a bath to be filled with such the solution.However, it is necessary to design an amount of time for soakingthereinto as sufficiently long, for removing as sufficiently such thecompound of silicon oxides in the vicinity of the surface thereof. Andthen therefor, due to the point of views of such as the total costtherefor, a management of such the acid solutions, or the like ingeneral, there is designed to be performed the removal of such thecompound of silicon oxides, that is adhered onto the surface thereof, asphysically and as mechanically therefor, with making use of a substance,that is so called as such as a brush, a buff, or the like.

Still further, in the case of rubbing the surface of the strip by makinguse of such as the brush, the buff, or the like, that are finished to beperformed the acid dissolution therefor, there becomes to be generated aconcave thereon and/or a convex thereon. And then thereby such theCorson alloy cannot help but become to have a surface thereof withhaving a relative roughness as relatively larger (that is approximatelyequal to be rough) even at an intermediate process for producingthereof. Furthermore, it is heretofore known that there becomes to bedeteriorated frequently the ability of plating thereof and the solderwettability thereof in the case where such the concave thereon and/orthe convex thereon is relatively large.

DISCLOSURE OF THE INVENTION

Moreover, such the subjects as mentioned above have not beenconsiderable for such as the conventional substance to be made use forthe lead frame or the like. However, in recent years, there becomes tobe increased a requirement of such as an environment resistant propertyunder an environment of a higher temperature and of a higher humidity, acorrespondence to the lead free soldering, or the like, and thenaccording to any one of the technologies as disclosed in the abovementioned each of the Japanese Patent Application Publications, therebecomes to be happened that it is not able to satisfy the property ofsuch as the ability of plating thereon, the solder wettability thereon,or the like. Therefore, with having regard to such the points at issueas mentioned above, and then here the subjects of the present inventionare to provide an copper alloy, that is superior in the ability ofplating thereon and the solder wettability thereon even under anenvironment for making use thereof as severe therefor, and that isapplicable as preferred to such as a lead frame for an electricalmachinery and apparatus and for an electronic equipment, a connectortherefor, a material for a terminal therein, or the like.

Here, the present inventors have investigated deeply regarding such thecopper alloy, that is applicable as preferred to the application of anelectrical and an electronic components, have been directing theirattention to a relative roughness on a surface of a strip to be producedby making use of such the copper alloy, and then there are found out arelationship that there becomes to be improved the ability of platingthereon of the material therefor and the solder wettability thereon ofthe material therefor in a case where a peak position regarding afrequency curve, that presents a concave component of a surfaceroughness and/or a convex component thereof, positions at the plus side(the side for the convex component thereof) comparing to an averagevalue of the curve for meaning the surface roughness thereof (a positionas zero regarding such the frequency curve). Moreover, the furtherexaminations are progressed therefor, and then it becomes able tocomplete the present invention hereby.

That is to say, according to the present invention, it becomes able toobtain a Cu—Ni—Si alloy (a Corson copper), that is superior in surfacequality thereof.

That is to say, according to the present invention, it becomes able tobe provided alloy strip materials as defined below.

1. A first aspect regarding a copper alloy strip material forelectrical/electronic components according to the present invention ischaracterized in that such the copper alloy strip material forelectrical/electronic components includes: Ni as between 1.5 mass % and4.0 mass %; Si as between 0.3 mass % and 1.5 mass %; and the balancebeing Cu and unavoidable impurities, wherein a mean roughness Ra of asurface roughness is not larger than 0.3 μm regarding the strip in adirection as right angle to a direction of a rolling therefor, a maximumheight Ry thereof is not higher than 3.0 μm regarding the same therein,and there is positioned a peak position regarding a frequency curve,that represents a concave component of the surface roughness and/or aconvex component thereof, at the plus side (the side for the convexcomponent) comparing to an average value of the curve that means thesurface roughness thereof.

2. A second aspect regarding a copper alloy strip material forelectrical/electronic components according to the present invention ischaracterized in that such the copper alloy strip material forelectrical/electronic components includes: Co as between 0.5 mass % and2.0 mass %; Ni and Co in total as between 1.5 mass % and 4.0 mass %; Sias between 0.3 mass % and 1.5 mass %; and the balance being Cu andunavoidable impurities, wherein a mean roughness Ra of a surfaceroughness is not larger than 0.3 μM regarding the strip in a directionas right angle to a direction of a rolling therefor, a maximum height Rythereof is not higher than 3.0 μm regarding the same therein, and thereis positioned a peak position regarding a frequency curve, thatrepresents a concave component of the surface roughness and/or a convexcomponent thereof, at the plus side (the side for the convex component)comparing to an average value of the curve that means the surfaceroughness thereof.

3. A third aspect regarding a copper alloy strip material forelectrical/electronic components according to the present invention ischaracterized in that regarding such the copper alloy strip material forelectrical/electronic components as described in the above mentionedfirst or the second aspect, the copper alloy includes at least any oneof elements, that is selected from a group to be comprised of Sn, Zn, Crand Mg, as between 0.005 mass % and 1.0 mass % in total therefor.

The above and other aspects and advantages according to the presentinvention will be further clarified by the following description, withreference to the drawings to be attached as properly therefor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing to be excerpted from the JIS(B0601).

FIG. 2 is a relative roughness chart showing an example of a relativeroughness on a surface thereof.

FIG. 3 is a graph showing a result that there is made an analysis of therelative roughness chart as shown in FIG. 2, with making use of aconcave component therein and/or a convex component therein.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment to be preferred for a copper alloy strip materialaccording to the present invention will be described in detail below.

First of all, a composition of an copper alloy to be made use for suchthe copper alloy material according to the present invention will bedescribed in detail below.

Here, there is designed a content of Ni therein to be as between 1.5mass % and 4.0 mass %, and it is further preferable to be as between 2.0mass % and 3.0 mass %. Moreover, there is designed a content of Sitherein to be as between 0.3 mass % and 1.5 mass %, and it is furtherpreferable to be as between 0.4 mass % and 0.7 mass %. Further,regarding a mass ratio between that of Ni therein and that of Sitherein, there is no limitation in particular thereto, however, it isdesirable to be as between 3.5/1 and 5.0/1 for the Ni/Si thereinrespectively.

Still further, regarding the Ra of such the copper alloy strip material,there is designed to be as not larger than 0.3 μm, and it is preferableto be as not larger than 0.2 μm. Still further, it is further preferablefor such the Ra to be as small as possible, and there is no limitationin particular for a lower limit thereof, however, such the value is notsmaller than 0.01 μm in normal. Still further, regarding the Ry thereof,there is designed to be as not higher than 3.0 μM, and it is preferableto be as not higher than 2.0 μm. Still further, it is further preferablefor such the Ry to be as low as possible, and there is no limitation inparticular for a lower limit thereof, however, such the value is notlower than 1.0 μm in normal.

Still further, according to the copper alloy strip material regardingthe present invention, there is designed to be controlled the peakposition regarding a frequency curve, that presents the concavecomponent of the surface roughness and/or the convex component thereof,to be positioned at the plus side (the side for the convex componentthereof), comparing to the average value of the curve for meaning thesurface roughness thereof (the position as zero regarding such thefrequency curve). Still further, the copper alloy strip materialaccording to the present invention means a rolled strip to be formed bymaking use of a rolling mill roll, and there is no limitation inparticular for such as a thickness thereof, for a width thereof, or thelike thereof. Still further, the same means that includes not only suchthe strip shape but also a bar shape as well.

Still further, according to a process for producing such the copperalloy material for electrical/electronic components regarding thepresent invention, first of all, there are performed a solution heattreatment, a hot rolling and then a cold rolling in the usual manner foran alloyed ingot, that is produced beforehand in the usual manner. Andthen thereafter, there is designed to be performed a heat treatmenttherefor, as desirably at between 400° C. and 550° C., and as desirablyfor between one hour and four hours. Next, there is designed to beperformed an acid cleaning therefor. Still further, there is nolimitation in particular regarding such the acid cleaning therefor,however, it is desirable therefor to be performed the cleaning thereforwith making use of the dilute acid with an amount of time for soakingthereinto as between five seconds and one hundred seconds, and it isfurther preferable therefor to be as between ten seconds and thirtyseconds.

Still further, regarding such the dilute acid therefor, it is able to beprovided such as a dilute sulfuric acid with having a concentration asnot higher than 20%, a dilute hydrochloric acid therewith, an aquafortis therewith, or the like. Still further, regarding each of such thedilute acids therefor, it is desirable to be made use each thereof withhaving the concentration as not higher than 10%.

Still further, it may be available to perform a treatment to bedegreased for such the rolled strip after performing the process of suchthe above mentioned heat treatment therefor. Still further, regardingsuch the treatment to be degreased therefrom, it is able to perform bymaking use of a method for soaking into any one of a variety of cleaningsolutions, such as an organic solvent of such as hexane, acetone,toluene, or the like, an aqueous solution of alkaline, such as sodiumhydroxide, calcium hydroxide, or the like.

Still further, according to such the acid cleaning therefor and/or thetreatment to be degreased therefrom, it becomes able to design to becontrolled the peak value regarding the frequency curve, that presentsthe concave component of the surface roughness and/or the convexcomponent thereof as an objet according to the present invention, to bepositioned at the plus side, comparing to the average value of the curvefor meaning the surface roughness thereof (the position as zeroregarding such the frequency curve).

Still further, according to the present invention, there is designed tobe performed a finishing rolling therefor at next thereto. Stillfurther, there is no limitation in particular regarding a rollingreduction rate of such the finishing rolling therefor, and it isdesirable therefor to be as not higher than 40%, and it is furtherpreferable therefor to be as between 5% and 40%.

Still further, there is received an effect on the relative roughness ofthe final product due to a relative roughness of a rolling mill roll tobe made use therefor. That is to say, there becomes to be transferredthe relative roughness of the rolling mill roll onto the materialtherefor, and then there is a tendency therein that the larger therelative roughness of the rolling mill roll to be made use therefor is,the larger the relative roughness of such the material to be rolledbecomes to be. However, in a case where there is designed to be smallerfor such the relative roughness of the rolling mill roll to be made usetherefor, there becomes to be minus for a forward slip thereof. And thenthereby it cannot help but become a process for rolling thereof under astate as slipped. As a result, there becomes to be affected asnegatively onto a work efficiency of rolling therefor, such as ageneration of any defect on the surface thereof, a running away of thestrip therefrom, or the like.

Furthermore, there is a limitation on the relative roughness to be ableto control at the process of the final rolling therefor. And then it isheretofore known as well that in a case of being rolled with a relativeroughness of a rolling mill roll to be made use therefor as equivalentto each of therebetween, the smaller the relative roughness of thematerial is, that is supplied before performing the process of such thefinal rolling therefor, and the larger the rolling reduction thereof is,the smaller thereby the relative roughness thereon becomes to be.

Here, the present inventors have examined in comprehensive mannersregarding such the findings as mentioned above, and then it is found outthat there becomes to be changed the ability of plating thereon and thesolder wettability thereon, by changing a ratio between the concavecomponent of the relative roughness and the convex component thereof ona strip material. that is to say, it is heretofore known that regardingthe surface roughness thereon, there is appeared each of the concavecomponent thereof and the convex component thereof as equally between acentral line as a border therefor, that corresponds to an average valueof such the components, however, it is found out that it becomes able tobe improved the ability of plating thereon and the solder wettabilitythereon, by changing in an intentional manner for the ratio between suchthe individual components.

Moreover, there may be effected on the relative roughness of the copperalloy strip material as the product to be objective for the presentinvention, by the relative roughness of the rolling mill roll at theprocess of the intermediate cold rolling therefor or that at the processof the finishing rolling therefor as well. Therefore, it is desirablefor the surface roughness of the above mentioned rolling mill roll atthe process of the intermediate cold rolling therefor to be controlledas the Ra thereof is between 0.2 μm and 0.6 μm and the Ry thereof isbetween 2 μm and 6 μm. Further, it is desirable for the relativeroughness of the above mentioned rolling mill roll at the process of thefinishing rolling therefor to be controlled as the Ra thereof is between0.02 μm and 0.15 μm and the Ry thereof is between 0.2 μm and 1.5 μm.

Still further, as described above, it is able to change the individualamounts of the concave component and the convex component regarding therelative roughness of the strip material, by changing such as the methodfor removing the compound of silicon oxides on the surface thereof, therelative roughness of the rolling mill roll, or the like. However, it isnot able to control the ratio between the concave component of therelative roughness and the convex component thereof on such the stripmaterial with an accuracy as higher. And then thereby there is remainedwithin a certain limit as only specifying such as the Ra, the Ry, or thelike, regarding the relative roughness on the surface thereof accordingto the above mentioned each of the patent documents.

On the contrary, according to the present invention, in a case ofperforming a finishing rolling for a material, that there is performedat first as repeatedly the heat treatment therefor and the acid cleaningtreatment therefor, and then thereafter that is soaked into the diluteacid (such as an aqueous solution of sulfuric acid as 10% therein or thelike) before performing the process of the final rolling therefor(before the process of the finishing rolling therefor), there becomes tobe appeared a peak position regarding a frequency curve, that representsthe concave component of the surface roughness and/or the convexcomponent thereof, at the plus side (the side for the convex component),comparing to an average value of the curve for meaning the surfaceroughness (a position as zero regarding such the frequency curve). Stillfurther, as similar thereto, in a case of performing a finishing rollingfor a material, that there is to be degreased therefrom beforehand (bybeing soaked into such as hexane, an organic solvent of such hexane asthe principal ingredient therein, or the like, a cleaning solution ofhydrocarbon based, or the like), there becomes to be appeared a peakposition regarding a frequency curve, that represents the concavecomponent of the surface roughness and/or the convex component thereof,at the plus side (the side for the convex component) as well, comparingto an average value of the curve for meaning the surface roughness (aposition as zero regarding such the frequency curve), as similarthereto.

Still further, a chemical state in a vicinity of the surface of such thematerial before performing the process of the final rolling therefor mayhave an effect on a state after the process of the final rollingtherefor. And then thereby it is able to be surmised that there becomesto be appeared each of such the peak positions regarding the individualfrequency curves, that individually represent the concave component ofthe surface roughness and/or the convex component thereof, at each ofthe plus side (the individual sides for the convex component), comparingto each of the average value of the individual curves for individuallymeaning the surface roughness (the individual positions as zeroregarding each of such the frequency curves), though there has not yetcleared a cause of such the phenomenon. For example, it is able to besurmised that there becomes to be appeared a difference on the removalof a surface layer thereon, such as an oxide film layer thereon, that isformed at the process of the heat treatment therefor before performingthe acid cleaning therefor, a work hardened surface layer thereon, thatis formed at the process of the cold rolling therefor before performingthe process to be degreased therefrom, or the like. And then thereby itis able to be considered that there may become to be changed a thicknessthereon to be removed therefrom, as a very small amount thereof, bymaking use of such as the acid cleaning therefor, the process to bedegreased therefrom, or the like.

Still further, there may be another factor that is caused by therelative roughness of the rolling mill roll at the process of thefinishing rolling therefor as well (there is existed both of the concavecomponent and the convex component in the relative roughness of such theroll as well). For example, there becomes to be increased the concavecomponents in such the material therefor in a case where there are a lotof convex components in the relative roughness of such the rolling millroll to be made use therefor. On the contrary thereto, there becomes tobe increased the convex components in such the material therefor in acase where there are a lot of concave components therein of such therolling mill roll to be made use therefor. That is to say, there becomesto be changed the relative roughness of such the material therefor andeach of the components in such the relative roughness thereof (theconcave components therein and/or the convex components therein), due tothe relative roughness of the rolling mill roll to be made use therefor.

Still further, in a case where the Ra of the relative roughness on thesurface of the material for the final product is designed to be as notlarger than 0.3 μm and also the Ry thereof as the maximum height thereofis designed to be as not larger than 3.0 μm, it becomes able to judgethat there becomes to be obtained the material therefor with having aproperty to be as superior in the solder wettability thereon and in theability of plating thereon in the case where there becomes to beappeared the peak position regarding the frequency curve, thatrepresents the concave component in the surface roughness thereof and/orthe convex component therein, at the plus side (the side for the convexcomponent), comparing to the average value of the curve for meaning thesurface roughness (the position as zero regarding such the frequencycurve).

Still further, the meaning of the case where there is existing such thepeak position regarding the frequency curve, that represents the concavecomponent in the surface roughness of such the material and/or theconvex component therein, as the component at the plus side comparing tothe average value of the curve for meaning the surface roughness thereon(the position as zero regarding such the frequency curve) is thatregarding a roughness curve therefor (a profile curve) whether therebecomes to be increased the convex component therein or there becomes tobe decreased the concave component therein, comparing to each of that inan average line therefor to be obtained by making use of a filteredwaviness curve therefor.

Furthermore, the solder wettability is a test for examining an amount oftime for a molten solder to become getting wet onto a surface of amaterial therefor, and for examining a change of a load therefor in theperiod thereof. And, in a case of an alloy that includes Si as acomponent in such the alloy, such as the Corson alloy or the like, therebecomes to be hard to take a roundabout way for such the solder onto anyconcave part thereon, and then thereby it becomes to be inferior in thesolder wettability thereon. Therefore, if there is reduced the concavecomponent thereon, it becomes able to be improved such the solderwettability thereon.

While, according to an electroplating therefor, there becomes to betrapped any hydrogen, that is generated in a period of plating therefor,at the concave part thereon, and then there may be happened a defect,such as that it is not able to adhere such the plating on such the partthereon, that there may be generated a swelling due to the platingtherefor because of the result that there is occurred a convergence ofan electric current on a periphery of such the concave part thereon, orthe like. Therefore, if there is reduced such the concave componentthereon, it is surmised that it becomes able to be decreased anincidence rate for such the defect, and then thereby it becomes able tobe improved the ability of plating thereon.

That is to say, in the case where there is less concave componentstherein on the surface of the material therefor, and also in the casewhere there is existing the peak position regarding the frequency curve,that represents the concave component in the surface roughness thereonand/or the convex component therein, at the plus side (the side for theconvex component) comparing to the average value of the curve formeaning the surface roughness thereon (the position as zero regardingsuch the frequency curve), it becomes able to be improved the solderwettability on such the material therefor and the ability of platingthereon.

Moreover, according to the present invention, regarding the abovementioned Cu—Ni—Si alloy, there may be contained at least any one ofelements to be additional thereinto, that is selected from a group thatis comprised of Sn, Zn, Cr and Mg, as between 0.005 mass % and 1.0 mass% in total. Further, there may be contained therein as further preferredto be as between 0.05 mass % and 0.5 mass % in total. That is becausesuch the element to be additional thereinto has an effect on animprovement of such as the withstand stress and relaxationcharacteristic (the withstand creep rupture property), the bendingworkability, the adherence of the solder thereon, or the like, inaddition to the strength of the final product and the electricalconductivity thereof, without spoiling the advantage according to thepresent invention for such the Corson alloy.

Still further, regarding such the strength thereof, it is able tosuperimpose a reinforcement of solid solution with making use of atleast any one of Sn, Zn and Mg, in addition to a reinforcement ofprecipitation regarding the compound of Ni and Si that is the aspectaccording to the present alloy system.

Still further, regarding such the withstand stress and relaxationcharacteristic (the withstand creep rupture property), it becomes ableto be improved according to the solid solution with making use of atleast any one of Sn, Zn and Mg, comparing to that in the case of anyadditive free materials.

Still further, regarding such the bending workability, it becomes ableto be improved such the workability in a case where a size of a graintherein becomes to be fine, and then an addition of Cr functions asdemonstrating an effect of refining such the size of the grain therein.

Still further, it is effective to make use of Zn regarding animprovement of the solder wettability thereon, as the same becomes to besegregated at an interface between the solder and a parent phase of Cu,and then as there becomes to have an advantage according to making usethereof that it becomes able to suppress a generation of any voidtherein, that may be generated due to a change with the lapse of time ofthe solder and of such the parent phase.

Still further, because there may be interrupted on the electricalconductivity thereof in a case where there is existing excessively alarge amount for any one of Sn, Zn, Cr and Mg therein, it is desirablefor an addition thereof to be controlled as not higher than 1.0 mass %in total. On the contrary thereto, it is desirable for such the additionthereof to be as not lower than 0.005 mass % in total as well, fordemonstrating the above mentioned advantage thereof.

Still further, the Co therein functions to substitute some amount of theabove mentioned compound of Ni and Si, and then the same functions tocontribute as becoming to be a compound of Ni—Co—Si to the strengththereof. And then in such the case thereof, it is desirable for thecontent of such the Co to be added thereinto as between 0.5 mass % and2.0 mass %, and also for becoming the content of such the Co therein andthe content of the Ni therein to become as between 1.5 mass % and 4.0mass % in total thereof.

Next, regarding a measurement of the relative roughness on the surfacethereof, there is performed such the measurement as pursuant to thedefinition of a surface roughness and the label thereof (B0601-2001) asdefined in the Japanese Industrial Standards (JIS). Moreover, it is oneof the points to evaluate an average line thereof, as similar to themethod for evaluating such as the Ra thereon, an Rt thereon, the Rythereon, or the like. Further, according to the above mentioned JISlabel, it is able to be evaluated such the average line thereof bymaking use of a filtered waviness curve. Still further, a component tobe come out to an upper side of such the average line thereof isreferred to as a convex component hereinafter, meanwhile, a component tobe come out to a lower side of such the average line thereof is definedto be as a concave component hereinafter. As more specifically therefor,there is shown in FIG. 1 that is excerpted from FIG. 1 (a) according tothe same JIS label. And then according to such the figure, the portionof the roughness curve therein to be come out to the upper side of suchthe average line therein is defined to be as the convex componenttherein, meanwhile, the portion thereof to be come out to the lower sidethereof is defined to be as the concave component.

Still further, according to such the measurement therefor at this timethereof, there is designed to be measured a relative roughness on asurface of a material therefor in a direction as vertical to a rollingtherefor. And then therefor, a sampling length thereof is assumed to beas 4 mm, that is to say, a value to be cut off becomes to be as 0.8 mm(that is pursuant to the above mentioned JIS label). Still further, arate for scanning thereon is set to be as 0.1 mm/sec. Still further,there is made use of a surface roughness measuring apparatus (SurfcorderSE3500) for such the measurement thereof, that is produced by KosakaLaboratory Ltd., and then there becomes to be 7500 points for the numberof data obtained by such the measurement due to such the measuringlength as 4 mm. And then thereafter, there becomes to be performed forsorting such the data into a component as an upper side (plus)) from anaverage line thereof and into a component as a lower side (minus)therefrom, there becomes to be plotted a frequency distribution thereof,and then there becomes to be performed an assessment therefor.

Still further, according to such the measurement therefor by making useof the above mentioned conditions therefor, there becomes to be existeda material that an average line thereof does not fit to a peak of afrequency distribution therefor, though it is considered therefor ingeneral that the other average lines are the lines for meaning theaverage of the convex components therein and the concave componentstherein. For example, there are shown charts ((1), (2), (3), and (4)) inFIG. 2 for showing the relative roughness regarding materials therefor,that are individually produced by following each of a variety ofconditions therefor respectively. Still further, there becomes to besorted the convex components therein and the concave components thereinwith making use of such the individual charts. And then thereafter,there is performed therefor to be re-plotted, with a vertical axistherein to be redefined as a frequency (%) thereof and a horizontal axistherein to be redefined as a roughness (μm) thereon respectively. Hence,there becomes to be obtained FIG. 3 thereby. And then according to suchthe plot, there becomes to be existed the material that has the peak ofthe frequency thereof at the concave component therein (the minus side),the material that has the peak thereof at the convex component therein(the plus side), and the material that has the peak thereof atapproximately zero, in a case of drawing a line for passing through theroughness as zero μm on the horizontal axis therein.

Furthermore, the present inventors have been directing their attentionto the material (1) according to such FIG. 3, that has the peak thereofas existing at the side thereof as the convex component therein, andthat becomes to be superior in the solder wettability thereon and in theability of plating thereon as well. And then according thereto, therebecomes to be presented the present invention hereby.

Thus, according to the present invention, by forming the Cu—Ni—Si alloy,and also by performing further the addition of at least any one of Sn,Zn, Cr, Mg and Co thereinto, it becomes able to provide the copperalloy, that is superior in such as the strength thereof, the electricalconductivity thereof, the withstand stress and relaxation characteristic(the withstand creep rupture property), the bending workability, theadherence of the solder thereon, or the like, and that becomes to beapplicable as preferred to the application of the electrical machineryand apparatus and of the electronic equipment.

EXAMPLES

Next, the present invention will be described in further detail below,with reference to the following examples, however, the present inventionwill not be limited to any one of such the examples.

Example 1

First of all, there is performed a dissolution for an alloy, thatcontains the components as shown in Table 1, and that is comprised of Cuand an unavoidable impurity as the remaining percentage thereof, bymaking use of a high frequency melting furnace, and then thereafterthere becomes to be casted by making use of such the alloy with a rateof cooling therefor as between 10° C. per second and 30° C. per second.Hence, it becomes able to obtain an ingot, which has a thickness as 30mm, a width as 100 mm and a length as 150 mm.

And then thereafter, there is performed to be maintained such the ingot,that is obtained thereby, at between 930° C. and 970° C. for between ahalf hour and one hour. Next, there becomes to be performed a hotrolling therefor to form a hot rolled strip with having a stripthickness of at as 12 mm, and then thereafter there becomes to beperformed a facing for both surfaces of such the strip to become the tthereof as 10 mm. Next, there becomes to be performed a finishingtherefor to become the t thereof as 0.3 mm by making use of a coldrolling therefor.

Next, regarding Process group A therein, there is performed a heattreatment therefor at between 425° C. and 500° C. for between one hourand four hours, and then thereafter there becomes to be performed asorting therefor into Treatment (1): a material that there is performedan acid cleaning for a surface thereof; Treatment (2): a material thatthere is performed to be degreased therefrom; and Treatment (3): amaterial that there is not performed either one of such the treatmentstherefor at all. And then thereafter there becomes to be performed afinishing rolling therefor. Thus, it becomes able to be produced each ofthe materials therefor. Moreover, for Treatment (1) there is made use ofan aqueous solution of a sulfuric acid as 10% therein, for Treatment (2)there is made use of hexane, and also there is designed an amount oftime for soaking each of thereinto to be as between ten seconds andthirty seconds respectively.

Further, regarding Process group B, there is performed a process of asolution heat treatment for a strip of at as 0.3 mm at between 850° C.and 950° C. for between ten seconds and thirty seconds. And thenimmediately thereafter there becomes to be performed a process of awater quenching therefor. Next, there becomes to be performed a processof the heat treatment therefor at between 425° C. and 500° C. forbetween one hour and four hours, as similar to Process group A, and thenthereafter there becomes to be performed the sorting such the stripsinto Treatments (1), (2) and (3). And then thereafter there becomes tobe performed a process of the finishing rolling for each thereofrespectively (regarding a roughness on each of the surfaces of therolling mill rolls therefor, there is made use each thereof with havingthe Ra as 0.03 μm and the Ry as 0.3 μm for Process group A, on thecontrary thereto, there is made use the other one thereof with havingthe Ra as 0.06 μm and the Ry as 0.71 μm for Process group B,respectively). Thus, it becomes able to be produced each of such thematerials therefor.

And then at last, with making use of the rolling mill roll as similarthereto for a process of the finishing rolling for each thereof, therebecomes to be performed such the process with a rate of the finishingtherefor such as 10%, 20%, 30%, or the like. Furthermore, there maybecome to be performed as required an annealing at a lower temperatureat between 300° C. and 450° C. And then thereafter there becomes to beperformed a test for characteristics regarding each of such the samplematerials.

Next, for each of such the sample materials, there is performed anexamination on the characteristics thereof as described below.

a. Relative Roughness

There is performed a measurement for a material in a direction asvertical to a rolling therefor. Moreover, there is performed such themeasurement as pursuant to JIS-B0601 (2001). Further, a length of themeasurement therefor is set to be as 4 mm, a value of to be cut offthereof is set to be as 0.8 mm (that is pursuant to the above mentionedJIS label), and a rate for scanning thereon is set to be as 0.1 mm/sec.Still further, there is made use of the surface roughness measuringapparatus (Surfcorder SE3500) for such the measurement therefor, that isproduced by Kosaka Laboratory Ltd. Still further, there is repeated suchthe measurement therefor with the number thereof as three times, andthen there becomes to be evaluated each of the averages for the Ra andfor the Ry respectively. Furthermore, regarding a convex componenttherein and a concave component therein, there becomes to be formed thegraph as shown in FIG. 3 with making use of the data of the measurementtherefor as three times thereof, and then there becomes to be judgedaccording to a confirmation whether a peak thereof exists at an upper(plus) component therein comparing to a line, that indicates theroughness thereon as zero μm, or at a lower (minus) component therein.And then in a case where there is existed a dispersion according to suchthe measurements as between the three times thereof, for example, in acase where there are existed the peaks at the upper side (plus)component therein according to such the measurements as the two timesthereof, there becomes to be judged that there is an amount for theconvex components as larger comparing thereto.

b. Solder Wettability

There is performed a measurement as pursuant to JIS-00053 (1996).Moreover, there is made use of the solder checker (SAT-5000), that isproduced by RHESCA Co., Ltd., for such the measurement thereof, and thenthere becomes to be performed thereof with a depth for soaking thereintoas 5 mm, a rate for soaking thereinto as 25 mm/sec, and an amount oftime for soaking thereinto as 10 seconds. Further, regarding anassessment therefor, there becomes to be performed such the assessmentto be as four classification therefor, that a result of the assessmenttherefor is defined to be as making use of a symbol as “double circle(excellent)” in a case where a zero cross time of a meniscograph isshorter than three seconds, that a result of the assessment therefor isdefined to be as making use of a symbol of “(good)” in a case where thezero cross time thereof is not shorter than three seconds but shorterthan six seconds, that a result of the assessment therefor is defined tobe as making use of a symbol as “Δ (acceptable)” in a case where thezero cross time thereof is not shorter than six seconds but shorter thannine seconds, and that a result of the assessment therefor is defined tobe as making use of a symbol as “X (no good)” in a case where the zerocross time thereof is not shorter than nine seconds.

c. Ability of Plating

There is performed a plating with making use of silver with a thicknessthereof to become as 1 μm, and then there is performed an assessmenttherefor. Moreover, regarding a surface preparation therefor, there isperformed to be degreased therefrom with making use of acetone, and thenthereafter there is performed to be degreased further therefrom bymaking use of a cathodic electrolysis with an electric current densityas 2.5 A/dm² in an aqueous solution of sodium hydroxide as 10% thereinfor approximately thirty seconds. Further, there becomes to be performedthereafter an acid cleaning therefor in a dilute sulfuric acid (10%) forapproximately thirty seconds. And then thereafter there becomes to beperformed such the plating with having an area thereon to become astwenty mm times fifty mm. Still further, regarding such the plating ofsilver thereon, there becomes to be performed therefor under a conditionthat the electric current density therefor is set to be as 1.0 A/dm² ata room temperature therefor, in a plating solution that includespotassium silver cyanide as 55 g/l, potassium cyanide as 75 g/l,potassium hydroxide as 10 g/l, and potassium carbonate as 25 g/l. Andthen after such the plating thereon, there becomes to be performed theassessment by observing any failure on such the plated surface thereofby making use of an optical microscope with a magnification thereof asfifty times therefor. Still further, regarding such the observationthereof, there is performed therefor by selecting three parts on suchthe plated surface thereof as arbitrarily therefor (so as not to beselected any edge parts on each of the test pieces for testing such theplating) with an area as ten mm times ten mm for each thereofrespectively. Still further, there becomes to be counted the number ofpieces for such as the swelling due to the plating thereon (with havinga diameter thereof as not less than 5 μm), the part that there becomesnot to be plated thereon (the defect), or the like. And then therebecomes to be obtained as the assessment therefor by summing up such thenumber of defects thereon that are found out at such the individualthree parts thereon. Furthermore, regarding criteria for such theassessment thereof, there are defined to be as making use of the symbolof “O” in a case where a summation of the failures in such theindividual three parts thereon is between zero and five pieces, to be asmaking use of the symbol as “Δ” in a case thereof as between six andtwenty pieces therein, and to be as making use of the symbol as “X” in acase thereof as not less than twenty-one pieces therein.

TABLE 1 Component in experimental material (mass %) Ni Si Sn Zn Mg Cr CoCu 1 2.3 0.55 0.15 0.5 0.1 — — Bal. 2 2.3 0.65 0.1 0.5 0.1 0.15 — Bal. 32.8 0.7 — — 0.12 — — Bal. 4 3.0 0.8 — — 0.1 — — Bal. 5 3.25 0.8 0.1 0.10.1 — — Bal. 6 3.5 0.85 0.15 0.05 — — — Bal. 7 3.75 0.88 0.5 0.1 0.05 —— Bal. 8 3.75 0.9 0.15 0.1 0.05 0.1 — Bal. 9 3.75 0.9 0.2 0.5 — 0.15 —Bal. 10 3.9 0.9 0.1 0.5 0.15 — — Bal. 11 2.5 0.58 — — — — — Bal. 12 1.50.6 — — — — 1.1 Bal. 13 2.0 0.55 — — — — 0.5 Bal. 14 2.1 0.65 0.15 0.5 —0.2 0.8 Bal. 15 2.4 0.7 0.07 0.5 0.15 — 1.0 Bal.

TABLE 2 Ra Ry PEAK SOLDER ABILITY OF ALLOY PROCESS TREATMENT (μm) (μm)POSITION WETTABILITY PLATING 1 GROUP A (1) 0.09 0.99 + ⊚ ◯ (2) 0.090.84 + ⊚ ◯ (3) 0.08 1.01 0 ◯ Δ GROUP B (1) 0.17 1.80 + ◯ ◯ (2) 0.141.60 + ◯ ◯ (3) 0.22 2.38 0 Δ Δ 2 GROUP A (1) 0.08 1.01 + ⊚ ◯ (3) 0.081.15 − Δ X GROUP B (1) 0.29 2.70 + ◯ ◯ (3) 0.15 1.59 0 Δ Δ 3 GROUP A (1)0.10 0.94 + ⊚ ◯ (2) 0.09 0.81 + ⊚ ◯ (3) 0.08 0.95 0 Δ Δ GROUP B (1) 0.171.77 + ◯ ◯ (2) 0.15 1.54 + ◯ ◯ (3) 0.22 2.36 − X X 4 GROUP A (2) 0.081.00 + ⊚ ◯ (3) 0.09 1.08 0 ◯ Δ GROUP B (2) 0.28 2.77 + ◯ ◯ (3) 0.15 1.580 Δ Δ 5 GROUP A (1) 0.08 1.02 + ⊚ ◯ (3) 0.09 1.16 − Δ X GROUP B (1) 0.282.68 + ◯ ◯ (3) 0.16 1.60 0 Δ Δ 6 GROUP A (2) 0.08 1.01 + ⊚ ◯ (3) 0.091.13 − Δ X GROUP B (2) 0.28 2.63 + ◯ ◯ (3) 0.15 1.62 − Δ X 7 GROUP A (1)0.09 1.01 + ⊚ ◯ (3) 0.09 1.11 0 ◯ Δ GROUP B (1) 0.28 2.77 + ◯ ◯ (3) 0.151.68 − Δ X 8 GROUP A (1) 0.09 1.00 + ⊚ ◯ (2) 0.09 0.95 + ⊚ ◯ (3) 0.080.99 − Δ X GROUP B (1) 0.18 1.78 + ◯ ◯ (2) 0.15 1.64 + ◯ ◯ (3) 0.22 2.25− X X 9 GROUP A (1) 0.07 1.04 + ◯ ⊚ (3) 0.09 1.04 0 ◯ Δ GROUP B (1) 0.282.68 + ◯ ◯ (3) 0.15 1.62 0 Δ Δ 10 GROUP A (1) 0.09 0.97 + ⊚ ◯ (3) 0.091.13 − Δ X GROUP B (1) 0.28 2.76 + ◯ ◯ (3) 0.15 1.60 0 Δ Δ 11 GROUP A(1) 0.09 1.07 + ⊚ ◯ (2) 0.08 1.30 0 Δ X GROUP B (1) 0.28 2.61 + ⊚ ◯ (2)0.25 1.69 − Δ ◯ 12 GROUP A (1) 0.08 0.99 + ⊚ ◯ (3) 0.09 1.22 − Δ Δ GROUPB (1) 0.22 1.76 + ⊚ ◯ (3) 0.18 2.62 − Δ Δ 13 GROUP A (1) 0.10 1.07 + ◯ ◯(2) 0.10 1.03 0 Δ X GROUP B (1) 0.28 1.99 + ◯ ◯ (2) 0.12 2.02 0 Δ X 14GROUP A (1) 0.10 1.37 + ◯ ◯ (3) 0.09 1.34 0 Δ X GROUP B (1) 0.29 1.76 +◯ ◯ (3) 0.12 1.90 − Δ X 15 GROUP A (1) 0.10 0.47 + ◯ ◯ (2) 0.11 0.73 − ΔX GROUP B (1) 0.29 2.96 + ◯ ◯ (2) 0.21 2.60 − Δ X

INDUSTRIAL APPLICABILITY

Such an copper alloy strip material according to the present inventionbecomes to be applicable as preferred to such as a lead frame for anelectrical machinery and apparatus and for an electronic equipment, aconnector therefor, a material for a terminal therefor, or the like, andfurther to an electrical and an electronic components, such as aconnector or a material for a terminal for mounting on a motor vehicle,a relay therefor, a switch therefor, or the like.

Thus, there is described as above regarding the present invention withthe embodiment therefor, however, the present invention will not belimited to every detail of the description as far as a particulardesignation therefor, and it should be interpreted widely withoutdeparting from the spirit and scope of the present invention asdisclosed in the attached claims.

Furthermore, the present invention claims the priority based on JapanesePatent Application No. 2007-260397, that is patent applied in Japan onthe third of October, 2007, and the entire contents of which areexpressly incorporated herein by reference.

1. An copper alloy strip material for electrical/electronic components,including: Ni as between 1.5 mass % and 4.0 mass %; Si as between 0.3mass % and 1.5 mass %; and a remaining percentage thereof to becomprised of Cu and an unavoidable impurity, wherein a mean roughness Raof a surface roughness is not larger than 0.3 μm regarding the strip ina direction as right angle to a direction of a rolling therefor, amaximum height Ry thereof is not higher than 3.0 μm regarding the sametherein, and there is positioned a peak position regarding a frequencycurve, that represents a concave component of the surface roughnessand/or a convex component thereof, at the plus side (the side for theconvex component) comparing to an average value of the curve for meaningthe surface roughness.
 2. An copper alloy strip material forelectrical/electronic components, including: Co as between 0.5 mass %and 2.0 mass %; Ni and Co in total as between 1.5 mass % and 4.0 mass %;Si as between 0.3 mass % and 1.5 mass %; and a remaining percentagethereof to be comprised of Cu and an unavoidable impurity, wherein amean roughness Ra of a surface roughness is not larger than 3 μmregarding the strip in a direction as right angle to a direction of arolling therefor, a maximum height Ry thereof is not higher than 3 μmregarding the same therein, and there is positioned a peak positionregarding a frequency curve, that represents a concave component of thesurface roughness and/or a convex component thereof, at the plus side(the side for the convex component) comparing to an average value of thecurve for meaning the surface roughness.
 3. The copper alloy stripmaterial for electrical/electronic components as defined in claim 1,wherein the copper alloy includes at least any one of elements, that isselected from a group comprised of Sn, Zn, Cr and Mg, as between 0.005mass % and 1.0 mass % in total.
 4. The copper alloy strip material forelectrical/electronic components as defined in claim 2, wherein thecopper alloy includes at least any one of elements, that is selectedfrom a group comprised of Sn, Zn, Cr and Mg, as between 0.005 mass % and1.0 mass % in total.